Read the docs at https://emodbus.github.io!

This is a library to provide Modbus client (formerly known as master), server (formerly slave) and bridge/gateway functionalities for Modbus RTU, ASCII and TCP protocols.

For Modbus protocol specifications, please refer to the Modbus.org site!

Modbus communication is done in separate tasks, so Modbus requests and responses are non-blocking. Callbacks are provided to prepare or receive the responses asynchronously.

Key features:

• for use in the Arduino framework
• designed for ESP32, various interfaces supported; async versions run also on ESP8266
• non blocking / asynchronous API
• server, client and bridge modes
• TCP (Ethernet, WiFi and Async), ASCII and RTU interfaces
• all common and user-defined Modbus standard function codes

This has been developed by enthusiasts. While we do our utmost best to make robust software, do not expect any bullet-proof, industry deployable, guaranteed software. See the license to learn about liabilities etc.

We do welcome any ideas, suggestions, bug reports or questions. Please use the "Issues" tab to report bugs and request new features and visit the "Discussions" tab for all else.

Have fun!